Drier



1950 T. EVANS 2,517,857 I DRIER Filed July 11, 1946 3 Sheets-Sheet 1 a o k E u I IN VEN TOR.

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DRIER ,Filed July 11, 1946 s Sheets-Sheet 2 & --------IIIIIIIWIIIIMII IIII ,"IIIIIHI IN VEN TOR.

Tao/ms EVA/V6 Aux-8,1950 T. EVANS 2,517,857

DRIER Filed July 11, 1946 s Sheets-Sheet s OUTER DRUM ham/:2 02am IN VEN TOR. Tim/was EVA/V8 Patented Aug. 8, 1950 Thomas Evans, Saginaw, Perkins 1110., Saginaw,

New York Mich, assignor to Baker Mich, a corporation of Application July 1 1, 1946, Serial No. 682,845

3 Claims. (Cl. 259- 109) This invention pertains to dryingapparatus for converting various fluid materials into powder or granular form.

More particularly, it pertains to means for application of heat to the primary material, for the removal of vapors that are thereby created, and for thecoincidental stirring, rotating, overturning, linear flow and cascading of the mass of material while it is'b'eing processed.

An object of my invention is to provide a drier of such type wherein the working chamber or space is in the form of an annular chamber, elongated and disposed with its central axis substantially horizontal and having its outer shell stationary and its inner shell rotatable. The improvement also comprises means for continually heating or cooling the material in the chamber, as may be required, both from the outside, as by means of steam jackets on the outer shell, and by steam circulation through the inner shell.

Another object is to provide such a drum assembly with scraper and agitator means for both outer and inner drum surfaces located in the working space between the drums and revolvable in the opposite direction to the rotation of the inner drum.

.An object is to provide such a drier with improved power driven rotating drums and scrapers that are simple, compact, relatively inexpensive to'manufacture and to maintain, and unusually effective in respect to efiiciency of heat transfer to or from the material and also in respect to the rapid and uniform conversion of the prime material from a, liquid or more or less viscous state to a state of uniform granulatedor drypulverized character.

Another object is to provide a unique coaxial drum and agitator arrangement, and a driving mechanism therefor, that shall be durable through a long life of service, under heavy duty. With the foregoing and'certain other objects in view which will appear later in the specifications, my invention comprises the'devices and combinations of elements and assemblies which will now be described and such modifications thereof as properly areincluded in the scope and spirit of the appended claims, forming a part of these specifications.

. Reference may-be had to the accompanying" drawings wherein the same letters of reference designate'the same or similar parts throughout the several views.

In the drawings:

Fig. 1 is a vertical longitudinal sectionalview,- partly broken away, showing a preferred arrange-i ment of the principal cooperating elements and assemblies that comprise a drier embodying my invention; I

Fig 2 is a side'view of the agitator scraper assembly, from which the driving mechanism is omitted;

Fig. 3 is a diagrammatic longitudinal sectional view of the bearing elements of Fig. 2, without the blades and their supporting lugs;

Figs. 4, 5, 6, '7, are transverse sectional views taken on lines 4, 5, 6, 1, respectively, in Fig. 2, to illustrate the fixed angularly displaced relationship that each blade section bears to the others.

My improved drier comprises, in general, three principal cooperating parts, Fig. 1. There is a stationary outer drum assembly; a rotatable inner drum assembly, and what may be termed a scraper-agitator assembly, the latter doing its work while rotating in the annular space S that exists in shell I of the stationary outer drum.

All three assemblies are coaxial. The material to be treated, for instance, by drying with steam or the like, is contained in the annular space S during-the processing operation. The inner drum is rotatable, say, in the counterclockwise sense, Figs. 4 to 7. The scraper-agitator is rotatable clockwise around the revolvinginner drum, like -a wheel hub that runs on a rotating hollow axle.

Auxiliary parts of my improvement pertain to compact simplified mountings and driving means for the principal parts alluded to above.

The outer drum assembly comprises a hollowelongated substantially horizontal cylindricalshell I supported in fixed position. It is provided with a suitable heat-transfer jacket 2 and has a charging inlet 3 and a discharge outlet 4 and an outlet 5 for vapor released from the material to vacuum or atmosphere.

The outer drum has end walls 6 that project upwardly fromthebase of the machine. Each end wall isprovided with a central stuffing box- 1 including a fluid-tight packing and a gland, preferably arranged as shown in Fig. 1.

451 The inner drum assembly consists of a hollow rotatable shell 8 contained within the stationary outer drum. The inner shell is somewhat shorter than the outer stationary drum and is coaxial therewith. End spaces 9 are thus provided "be: tween the headslfl, Ill of the inner drum and the end walls 6, 6 of the outer drum, the purpose of which is to receive rotatable flanges ll ofithe scraper-agitator assembly, as will bedescribed presently.

u "Each' head In of the inner drum has an axially extended externally packed quill shaft portion l2. Through one of them a heating medium such as steam can be supplied to the drum; and condensate can be withdrawn through the other.

The quill shaft is mounted to rotate in bearing sleeves [3 provided in a tubular axle M of the scraper-agitator assembly, which will now be de scribed.

The scraper-agitator assembly which is illustrated in a preferred form in Figs. 2 to '7, bears a general resemblance to the rotating member of a squirrel cage or to the knives of a lawn mower, but it is of different design, construction, arrangement and mode of operation.

My scraper-agitator assembly comprises two tubular axles spaced apart endwise, as indicated at [6, Fig. 3, with the plate flanges H, H on their inner ends.

A suitable number of rotatable sleeves I5 are spaced apart between the opposed flanges H, as shown. The sleeves i 5 are in fact rotary bearing rings with smooth inner surfaces that ride around upon the external face of the inner drum shell 8 as a bearing, Fig. 4, while the drum itself is rotating in the opposite sense.

As shown in Figs. 2 and 3, the plate flanges i i on the tubular axles M and the intermediate sleeves l5 divide the working length it of the scraper-agitator assembly into four sections designated by the broken lines 4, 5, 8, l. Each section may be regarded as a squirrel-cage arrangement comprising three longitudinally disposed and peripherally spaced blades; one blade H is adapted to scrape material from the outside surface of the inner drum; another blade i 8 scrapes the interior surface of the outer drum; and the third askew blade ill is adapted to mix and stirand lift the material during the drying operation while also moving it progress vely from the ends of the scraper-agitator assembly toward its midlength. Blade I9 need not be a scraping blade.

The ends of the three blades are supported by lugs which are fixed to the flanges H of the axles M. The ends of other blades are carried by lugs that are fixed to the rotatable sleeves l5, as shown in Fig. 2, and Figs. 4 to 7. The outer ends of the blades (in sections 4 and 'i) are supported by the flange plates ll of the tubular axles i4.

Referring now more in detail to Figs. 4 to 7, which are end views, somewhat enlarged, taken in planes indicated by lines t, 5, t, I, Fig. 2; there is shown in cross-section, at Figs. 5 and 6, the inner revolving drum and also the rotatable sleeves it that slide rotatably as bearings upon the drum and carry the scraping and mixing blades [1, 18, I 9; The several views of this series are arranged in the regular order indicated in Fig. 2. They illustrate a preferred circularly staggered arrangement of the several bladecarrying sections relatively to each other, adapted to give smooth action with a uniform torque.

The two tubular axles M, M at the ends of the bladeassembly are rotatably mounted in liquidtight packing boxes 2| mounted in the opposite end walls 6, 6 of the outer drum, as shown in Fig. 1. The outer ends of axles [4, Hi are supported in outboard journal bearings 22, 22. Drivegea-rs 23, 23 are fixed on the axles Hi intermediate each stufifing box 2| and the outboard bearing 22; Meshing with these gears 23 are pinions' 2d, 24, which are fixed to a single master shaft 25 that is driven from any suitable source of power suchas that represented by the primary chainsprocket 26.

.Thus, sprocket 26 serves to rotate t W i tubular axles l4, l4 and their opposed flanges H, II, thereby actuating all the scraping and mixing and stirring blades simultaneously and so preventing material from adhering to the inner end walls 6 of the outer drum or to its inner cylindrical surface I. Also, the outer surface 8 of the inner drum is kept scraped clean. In addition all material in the annular space S between the two drums is mixed and urged toward the lower middle outlet 4.

The finished granular or powdery dry product is discharged through the lower outlet 4 after the desired degree of dryness and of granulating or powdering has been attained.

In operation, the drier is charged with the fluid, which is to be reduced from a wet state to dry granules or powder, by pouring it into the outer drum through the charging inlet 3, the quantity being preferably sufiicient to fill the annular space S between the drums up to about the level of the axis. The inlet 3 is then closed and, in case of operation by vacuum, the vapor outlet Elis put into communication with a space which is kept at lower than atmospheric pressure. The primary sprocket '26 is then put in rotation. It turns the master shaft 25 and pinions 24, 24. The'drive gears 2 5, 23 rotate the tubular axles i4 and their flanges H, thereby revolving the scraper-agi ator assembly, Fig. 2, in, say, a direction indicated by the curved arrows in Figs; 4 to 7 inclu ive. At the same time the master shaft 25 rotates-a drive sprocket 2! and a driven sprocket 28. These s rockets are connected by a drive chain, omitted from Fig. 1 for the sake of clearness. The sprocket 28 t rns the inner drum by means of one of the qu ll shafts H2, in the direction indicated by the curved arrow near the numeral H5 in Fig. 1, counter to the revolution of the scraping and agita ing blades H, 98, I9.

If the operation being considered is one wherein. vapor is being driven off from a'liouid or other fluid material for the purpose of recovering the residual ingredients in dry granular or powder form, or in a fragmented partly dried state, the outer drum is heated by application of steam or the like to shell I, in known manner.

Similarly. the interior of shell 3 is heated by supplying steam; for example through the incondition to its final condition, 'the blades 'IT,{ 3, i9 in each of the sets 4, 5 6, 1, Fig. 4,".are,

respectively, scraping the outer face of the inner rotating drum clean with each turn of the drum; "scraping the inner face of the outer stationary drum and agitating mixing, dipping, and pouring the material while urging it toward the mid length of the hot shells of the drums. Heat transference is carried on efiiciently' by this arrangement by' keeping the walls clean and by pouring the material from above onto the hot top'of the inner drum as the blades drain intheir topposition.

In the granulating stage the particles fall down onto the hot shell'B and take up an added quantity' of heat by direct contact with the shell, so

that drying can be quickly completed in a very thorough manner, as is done in certain types of earlierdriers used in the final evaporating step of manufacture of common salt and similar material.

If desired a number of driers such as described above may be connected together in series and known in the art as multiple effect evaporators; using the vapor discharge from the outlet 5 as the live heating agent for the next evaporating and drying unit.

Having described my invention, what I claim as my invention and desire to secure by Letters Patent is:

1. In a drier of the character described wherein a stationary outer drum surrounds a coaxial revolvable inner drum; a scraper-agitator assembly revolvable in the space between said drums; a series of spaced bearing rings slidingly rotatable around said revolvable inner drum; peripherally spaced lugs on said rings; blades on said lugs of which at least one is a scraping blade adapted to operatively engage the exterior surface of the said revolvable inner drum; another scraping blade similarly adapted to engage the interior surface of the said stationary outer drum; and a mixing blade set askew; operative means for rotating the inner drum in one direction and the scraper-agitator mechanism simultaneously in the opposite direction.

2. A scraper agitator for a drier comprising tubular axles spaced apart endwise, having plate flanges on their inner ends; rotatable sleeves spaced apart between said flanges; lugs extending outwardly from said plate flanges and said sleeves; blades disposed longitudinally and staggered circularly on said lugs, in sections; each section comprising an outside surface scraper blade, an inside surface scraper blade, and an askew mixer blade.

3. Scraper-agitator structure as :claimed in claim 2, wherein the mixer blade of each section is arranged peripherally relatively to like blades of adjacent sections so as to present an askew arrangement of said blades adapted to urge material from the ends of the scraper-agitator assembly toward its mid-length.

THOMAS EVANS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 830,521 Passburg Sept. 11, 1906 1,672,218 I-Iow June 5, 1928 2,089,093 Hougland Aug. 3, 1937 2,188,220 Carlson Jan. 23, 1940 2,281,944 Miller et al. May 5, 1942 

